Final answer:
Potential blood donors must pass certain tests to ensure the safe use of their blood, including determining their blood type and confirming they are in good health and free from transmissible diseases.
Step-by-step explanation:
Before being eligible to donate blood, potential donors must undergo several tests to ensure their blood is safe and suitable for use. The key conditions checked are blood type, health status, and risk factors for transmissible diseases.
Blood type is crucial as it must be compatible with the recipient. It is identified using cross-matching tests which involve adding commercially prepared antibodies to red blood cells. For the donor, this confirms the blood type, while for the recipient, it ensures compatibility, reducing the risk of a transfusion reaction.
Donors must also be in good health. Despite common misconceptions, individuals with controlled high blood pressure (below 180/100) or who are on blood pressure medications can donate as long as their condition is stable. Those with high cholesterol are also typically eligible.
Finally, there are stringent measures in place for testing HIV and other infectious diseases. Donated blood is carefully screened, and new needles are used for each donation to prevent the transmission of viruses.